It's not that the stock OS is too taxing, it's that the CPU in the SmartQ 5 and 7 isn't powerful enough to handle video. Apparently there is a video chip in the devices, but there is no driver for it in the stock OS (or by Mer), unless it is used by WinCE that won't be any better.

as long as the hardware is there we can only hope that one day the software will catch up. but this sucks lol